It is well known in motor vehicles to provide an air bag assembly which inflates to restrain a vehicle occupant. An air bag inflator is mounted on the vehicle body forwardly of the vehicle seat. The air bag is mounted on the inflator so that activation of the inflator will generate gas to fill the air bag and expand the air bag from a folded-up stored condition to an inflated position in which the air bag fills the space in front of the seated occupant. A typical air bag includes an upper portion for restraining the upper torso and a lower portion for restraining the lower torso.
It is desirable to shape the air bag to tune the occupant restraining characteristics of the air bag assembly.